Snap action pneumatic relay

ABSTRACT

A miniature pneumatic snap action relay having a bistable snap disc arranged to interconnect first and second sets of two ports when in one stable position and to interconnect third and fourth sets of two ports when in the other stable position.

United- States Patent 1 Hogel 51 Jan. 2, 1973 s41 SNAP ACTION PNEUMATICRELAY 3,426,800 2/1969 Bauer ..235/20| ME 3,490,479 1/1970 Mott ..137/82[75] Jmph 3,590,694 7/1971 Prescott ..137/s2 Assignee; Honeywell, Inc.Minneapolis Minn 3,633,605 1/1972 Smith ..137/512.15

[22] Filed: Sept 1971 Primary Examiner-M. Cary Nelson [21] App1 No.;182,995 Assistant Examiner-William H. Wright v Attorney-Lamont B. Koontzand Marvin T. Fayanske [52] US. Cl. ..137/119, 137/82, 137/112,

137/516.25, 137/516.29 [57] ABSTRACT [51] Int. Cl. ..Fl5b 5/00, GOSd16/06, F15c 3/04 A miniature pneumatic snap action relay having a [58]Field of Search ..137/119, 100, 101, 516.25, bistable snap disc arrangedto interconnect first and 137/516.27, 516.29, 512.15, 512.4, 118, secondsets of two ports when in one stable position 111, 112, 109, 102, 82;235/201 and to interconnect third and fourth sets of two ports when inthe other stable position. [56] References Cited 10 Claims, 3 DrawingFigures UNITED STATES PATENTS r 3,326,237 6/1967 Frick 137 102 PATENTED2 7 SHEET 1 OF 2 FIG. I

INVENTOR. JOSEPH E7 HOGEL BY M a. M?

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to apneumatic relay and more particularly to a snap acting pneumatic relaycapable of performing a plurality of functions.

As pneumatic diaphragm logic circuits have become increasinglyminiaturized, there has arisen a need for a miniature snap acting relaycapable of performing a multitude of logic functions. Such arelay'should be inexpensive, highly reliable, and easily manufacturable.

The subject invention fulfills all of these needs. It comprises ahousing having a cavity divided by a flexible diaphragm into twopressure chambers. Oppositely disposed in the two pressure chambersaretwo sets of two concentric nozzles. Forming part of the diaphragm is abistable snap disc which is disposed between the two sets of twonozzles. The bistable snap disc is arranged so that when it is in one orthe other of its two stable positions, it allows communication betweenthe two nozzles in one pressure chamber and at the same time closes offone of the nozzles in the other pressure chamber and allowscommunication between the other nozzle and the other pressure chamber.

The relay may be used as an oscillator, as a feed and bleed device, oras an element which may serve any number of purposes in pneumaticcontrol circuits. Specific uses and advantages of the snap actionpneumatic relay of the subject invention will become apparent upon areading of the detailed description of the invention in view ofthedrawing.

DESCRIPTION OF THE DRAWING FIG. 1 is an exploded view of the snap actionpneumatic relay. I

FIG. 2 is a cross sectional view of the snap action pneumatic relayarranged to function as an oscillator.

FIG. 3 is a cross section of the snap action pneumatic relay arranged toprovide a feed-bleed function.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 there is shown anexploded view of the snap action pneumatic relay which includes twohalves, and 11, of a housing and a flexible diaphragm 12 interposedbetween the halves of the housing. The diaphragm means 12 is preferablytwo thin layers of a rubber material or the like between which issandwiched a force responsive means or snap disc 13. The housing halves10 and 11 are substantially identical, each having a cavity 14 in whichare disposed two annular concentric partitions l5 and 16. The housinghalf 11 is provided with ports 19, 18, and 17 which communicaterespectively with the interiors of the annular partition 16, annularpartition 15, and the cavity 14. Housing half 10 is provided with ports20, 21, and 22 which communicate with like portions of housing half 10.The snap disc 13 is arranged within the layers of the diaphragm means 12so as to be centrally located and is further sized so as to cover thelarger partition means 15. The housing halves 10 and 11 and thediaphragms 12 may be fastened together by any suitable means such as anadhesive, bolts, etc.

In FIG. 2 a snap action pneumatic relay is illustrated with connectionsfor providing an oscillator. Again the housing means 30 has a cavitytherein which is divided by the diaphragm means 31 into a first pressurechamber 32 and a second pressure chamber 33. In communication with thefirst pressure chamber 32 is a first port 34; in communication with thesecond pressure chamber 33 is a second port 35. The annular partitionsdisposed within the first pressure chamber 32 define first and secondnozzles 36 and 37. The oppositely disposed annular partitions in thesecond pressure chamber 33 define the third and fourth nozzles 38 and39. The first and third nozzles 36 and 38 are connected via conduit 40through a variable restriction 41 to a source of main pressure 42. Thesecond nozzle 37 is connected via conduit 43 to the first port 34 andalso to a restricted bleed 44 and an outlet 45. The fourth nozzle 39 isconnected via conduit 46 to the second port 35 and also to a restrictedbleed 47 and another outlet 48.

The diaphragm means 31 preferably comprises two thin layers ofrubber-like material between which is disposed a force responsive means49. This force responsive means 49 comprises a bistable snap disc havingover center action. The snap disc is preferably sized so as to have adiameter greater than the diameter of the second and fourth nozzles 37and 39. In addition the snap disc 49 is sufficiently cup shaped so thatwhen it is in its second stable position as shown in FIG. 2 itsimultaneously closes off the first nozzle 36 from the second nozzle 37and allows the third nozzle 38 and the fourth nozzle 39 to communicatewith each other but not with the second pressure chamber 33. When thesnap disc 49 is in its first stable position, it closes off the thirdnozzle 38 while allowing the fourth nozzle 39 to communicate with thesecond pressure chamber 33; simultaneously the force responsive means,or snap disc 49, closes off the second nozzle 37 from the first pressurechamber 32 while allowing the first and second nozzles 36 and 37 tocommunicate with each other.

The oscillator of FIG. 2 operates as follows:

When the force responsive means 49 is in its second position as shown inFIG. 2, the source of main air pressure 42 provides air throughrestriction 41, through conduit 40, to the third nozzle 38. The airpressure is transmitted from the third nozzle 38 into the fourth nozzle39 and then through'conduit 46 into the second port 35 and the secondpressure chamber 33. Assuming the outlet 48 is connected tosubstantially deadended device, such as a pressure gage, the pressure inthe second pressure chamber 33 will build up until the pressure on thediaphragm 31 will cause the force responsive means or snap disc 49 tosnap into its first stable position. The pressure required for snappingthe force responsive means 49 from one stable position to the other is afunction of the operative area of the diaphragm 31 and of the inherentdifferential or resiliency of the snap disc 49. When the snap disc iscaused to move from its second stable position to its first stableposition, the pressure in the second pressure chamber will bleed downthrough the restricted bleed 47. At the same time, pressure from themain pressure source will be fed through the variable restriction 41,through the first nozzle 36, through the second nozzle 37, the conduit43, and the first port 34 into the first pressure chamber 32. When thepressure has sufficiently built up in the first pressure chamber 32, thesnap disc will be caused to snap into its second position as shown inFIG. 2 and one cycle of oscillation will have been completed. Thepressure in the first pressure chamber will thereafter bleed downthrough restricted bleed 44, and the cycle will repeat itself. Thefrequency of this oscillation may be varied by varying the restrictedbleed 41.

The snap action pneumatic relay illustrated in FIG. 3 is arranged toprovide a feed and bleed function. Fewer than all of the available portsor nozzles in the relay are utilized in performing this function. Afirst pressure port 50 in communication with the first pressure chamber32 is connected to a branch pressure source which may be provided by apneumatic thermostat or the like. A second pressure port 52, incommunication with the interior of the first nozzle means 36, providesan exhaust port to atmosphere. A third port 53 is in communication withthe interior of the second nozzle means 37 exterior to the first nozzle36. This port 53 provides an outlet which may be connected to a valve orthe like not shown. A fourth port 54 is in communication with theinterior of the second pressure chamber 33 and is connected to apressure regulating valve 55. Fifth and sixth ports 56 and 57 which arein communication with the interiors of the third and fourth nozzles 38and 39 respectively are blocked off by suitable means 58.

The force responsive means or snap disc 49 is again arranged to,allowthe second and third ports 52 and 53 to communicate when in its firststable position as illustrated in FIG. 3. When in its second stableposition, the snap disc 49 closes off the second port 52.

In operation, whenthe branch pressure is somewhat greater than theoutput of the pressure regulating valve 55, the snap disc 49 is forcedinto its second stable position thereby closing off the exhaust port 52and allowing branch pressure to be communicated through the firstpressure chamber 32, through the second nozzle 37 and out through port53. When the branch pressure falls below the output of the pressureregulating valve 55, the snap disc 49 is forced by thediaphragm means 31into its first stable position as illustrated in FIG. 3 therebypreventing communication between the branch port 50 and the output orthird port 53. At the force responsive means associated with thediaphragm means, the force responsive means having an over center snapaction and having first and second stable positions;

first and second ports in communication with the first and secondpressure chambers respectively; first and second nozzle means disposedwithin the first pressure chamber;

the force responsive means arranged to allow the first and second nozzlemeans to communicate when in its first stable position, and to allow thefirst port and second nozzle means to communicate when in its secondstable position.

2. The invention according to claim 1 wherein the force responsive meansif further arranged to close off the first nozzle means when in itssecond stable position.

3. The invention according to claim 1 additionally comprising third andfourth nozzle means disposed within the second pressure chamber meansoppositely of the first and second nozzle means in the first pressurechamber, the force responsive means further arranged to allow the secondport and the fourth nozzle means to communicate when in its first stableposition, and to allow third and fourth nozzle means to communicate whenin its second stable position.

4. The invention according to claim 3 wherein the force responsive meansif further arranged to close off the first nozzle means when in itssecond stable position and to close off the third nozzle means when inits first stable position.

5. The invention according to claim 4 wherein the force responsive meanscomprises bistable snap disc same time port 53 is allowed to communicatewith port 52 thereby allowing the pressure in the conduit connected tothe port 53 to exhaust through port 52. Thus a feed-bleed function isprovided by the embodiment of the snap action pneumatic relayillustrated in FIG. 3. This feed-bleed function obviates the use of arestricted bleed in a conduit leading to a controlled device such as avalve or the like. A bleed is thus eliminated, there being an exhaustingof the pressure to the control device only when the branch pressurethereto is cutoff.

While only one of the many possible embodiments of the subject inventionhave been described and only within the context of specific uses, it isintended that the scope of the invention described herein be limitedonly by the scope of the intended claims.

The embodiments of the invention in which an exclusive property or rightis claimed are defined as follows:

1. Fluid switching apparatus comprising:

housing means having a cavity therein;

diaphragm means dividing the cavity into first and second pressurechambers;

means, the first and second nozzle means are concentric, and the thirdand fourth nozzle means are concentric.

6. A snap action pneumatic relay comprising:

housing means having a cavity therein;

diaphragm means dividing the cavity into first and second pressurechambers;

bistable force responsive means having an over center snap action withfirst and second stable positions, the bistable force responsive meansassociated with the diaphragm means;

first and second concentric annular partitions means disposed within thefirst pressure chamber, the first partition means being interior to thesecond partition means;

a first port in the housing in communication with the interior of thefirst partition means;

a third port in the housing in communication with the interior of thesecond partition means, exterior of the first partition means;

a fourth port in the housing in communication with the second pressurechamber; 7

the bistable force responsive means arranged to allow the second andthird ports to communicate when in its first stable position, and toallow the first and third ports to communicate when in its second stableposition.

7. The invention according to claim 6 wherein the force responsive meansis further arranged to cut off communication between the second andthird ports when in its second stable position.

8. The invention according to claim 6 additionally comprising:

third and fourth concentric annular partition means disposed within thesecond pressure chamber oppositely of the first and second concentricannular partition means within the first pressure chamber, the thirdpartition means being interior to the fourth partition means;

a fifth port in the housing in communication with the interior of thethird partition means;

a sixth port in the housing in communication with the interior of thefourth partition means, exterior to the third partition means;

the bistable force responsive means further arranged to allow the fourthand sixth ports to communicate

1. Fluid switching apparatus comprising: housing means having a cavitytherein; diaphragm means dividing the cavity into first and secondpressure chambers; force responsive means associated with the diaphragmmeans, the force responsive means having an over center snap action andhaving first and second stable positions; first and second ports incommunication with the first and second pressure chambers respectively;first and second nozzle means disposed within the first pressurechamber; the force responsive means arranged to allow the first andsecond nozzle means to communicate when in its first stable position,and to allow the first port and second nozzle means to communicate whenin its second stable position.
 2. The invention according to claim 1wherein the force responsive means if further arranged to close off thefirst nozzle means when in its second stable position.
 3. The inventionaccording to claim 1 additionally comprising third and fourth nozzlemeans disposed within the second pressure chamber means oppositely ofthe first and second nozzle means in the first pressure chamber, theforce responsive means further arranged to allow the second port and thefourth nozzle means to communicate when in its first stable position,and to allow third and fourth nOzzle means to communicate when in itssecond stable position.
 4. The invention according to claim 3 whereinthe force responsive means if further arranged to close off the firstnozzle means when in its second stable position and to close off thethird nozzle means when in its first stable position.
 5. The inventionaccording to claim 4 wherein the force responsive means comprisesbistable snap disc means, the first and second nozzle means areconcentric, and the third and fourth nozzle means are concentric.
 6. Asnap action pneumatic relay comprising: housing means having a cavitytherein; diaphragm means dividing the cavity into first and secondpressure chambers; bistable force responsive means having an over centersnap action with first and second stable positions, the bistable forceresponsive means associated with the diaphragm means; first and secondconcentric annular partitions means disposed within the first pressurechamber, the first partition means being interior to the secondpartition means; a first port in the housing in communication with theinterior of the first partition means; a third port in the housing incommunication with the interior of the second partition means, exteriorof the first partition means; a fourth port in the housing incommunication with the second pressure chamber; the bistable forceresponsive means arranged to allow the second and third ports tocommunicate when in its first stable position, and to allow the firstand third ports to communicate when in its second stable position. 7.The invention according to claim 6 wherein the force responsive means isfurther arranged to cut off communication between the second and thirdports when in its second stable position.
 8. The invention according toclaim 6 additionally comprising: third and fourth concentric annularpartition means disposed within the second pressure chamber oppositelyof the first and second concentric annular partition means within thefirst pressure chamber, the third partition means being interior to thefourth partition means; a fifth port in the housing in communicationwith the interior of the third partition means; a sixth port in thehousing in communication with the interior of the fourth partitionmeans, exterior to the third partition means; the bistable forceresponsive means further arranged to allow the fourth and sixth ports tocommunicate when in its first stable position, and to allow the fifthand sixth ports to communicate when in its second stable position. 9.The invention according to claim 8 wherein the bistable force responsivemeans is further arranged to cut off communication between the secondand third ports when in its second stable position and to cut offcommunication between the fifth and sixth ports when in its first stableposition.
 10. The invention according to claim 9 wherein the bistableforce responsive means comprises snap disc means.